[llvm] r314801 - [Dominators] Add DFS number verification
Jakub (Kuba) Kuderski via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 3 14:27:04 PDT 2017
I submitted the fix for DT::eraseNode issue in r314847.
On Tue, Oct 3, 2017 at 4:46 PM, Jakub (Kuba) Kuderski <
kubakuderski at gmail.com> wrote:
> Well, I don't know why it's failing by just looking at it. I'll submit a
> fix for the LoopRotate bug in a moment and will see it unbreaks this
> buildbot.
>
> On Tue, Oct 3, 2017 at 4:42 PM, Juergen Ributzka <juergen at ributzka.de>
> wrote:
>
>> I don't know if this is reproducible on Linux, but the file that is
>> failing is common code in compiler-rt (sanitizer_libc.cc.o).
>>
>> On Tue, Oct 3, 2017 at 1:32 PM, Jakub (Kuba) Kuderski <
>> kubakuderski at gmail.com> wrote:
>>
>>> Hi Juergen,
>>>
>>> It seems like the patch caught some invalid DominatorTrees :).
>>>
>>> I'm now investigating a failure in LoopRotation happening in
>>> test/Transforms/ArgumentPromotion/pr3085.ll with expensive checks
>>> enabled, but I don't know if that's related.
>>> I looked and the buildbot's output and it seems to fail on OSX -- do you
>>> know if it's reproducible on x86_64 linux?
>>>
>>> Best,
>>> Jakub
>>>
>>> On Tue, Oct 3, 2017 at 4:26 PM, Juergen Ributzka <juergen at ributzka.de>
>>> wrote:
>>>
>>>> Hi Jakub,
>>>>
>>>> I think this broke one of our jobs on Green Dragon:
>>>> http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-ex
>>>> pensive/8568/consoleFull
>>>>
>>>> Could you please take a look?
>>>>
>>>> Thanks
>>>>
>>>> Cheers,
>>>> Juergen
>>>>
>>>> On Tue, Oct 3, 2017 at 7:33 AM, Jakub Kuderski via llvm-commits <
>>>> llvm-commits at lists.llvm.org> wrote:
>>>>
>>>>> Author: kuhar
>>>>> Date: Tue Oct 3 07:33:41 2017
>>>>> New Revision: 314801
>>>>>
>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=314801&view=rev
>>>>> Log:
>>>>> [Dominators] Add DFS number verification
>>>>>
>>>>> Summary:
>>>>> This patch teaches the DominatorTree verifier to check DFS In/Out
>>>>> numbers which are used to answer dominance queries.
>>>>> DFS number verification is done in O(nlogn), so it shouldn't add much
>>>>> overhead on top of the O(n^3) sibling property verification.
>>>>> This check should detect errors like the one spotted in PR34466 and
>>>>> related bug reports.
>>>>>
>>>>> The patch also cleans up the DFS calculation a bit, as all constructed
>>>>> trees should have a single root now.
>>>>>
>>>>> I see 2 new test failures when running check-all after this change:
>>>>>
>>>>> ```
>>>>> Failing Tests (2):
>>>>> Polly :: Isl/CodeGen/OpenMP/reference-a
>>>>> rgument-from-non-affine-region.ll
>>>>> Polly :: Isl/CodeGen/OpenMP/two-paralle
>>>>> l-loops-reference-outer-indvar.ll
>>>>>
>>>>> ```
>>>>> which seem to happen just after `Create LLVM-IR from SCoPs` -- I
>>>>> XFAILed them in r314800.
>>>>>
>>>>> Reviewers: dberlin, grosser, davide, zhendongsu, bollu
>>>>>
>>>>> Reviewed By: dberlin
>>>>>
>>>>> Subscribers: nandini12396, bollu, Meinersbur, brzycki, llvm-commits
>>>>>
>>>>> Differential Revision: https://reviews.llvm.org/D38331
>>>>>
>>>>> Modified:
>>>>> llvm/trunk/include/llvm/Support/GenericDomTree.h
>>>>> llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h
>>>>>
>>>>> Modified: llvm/trunk/include/llvm/Support/GenericDomTree.h
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/
>>>>> Support/GenericDomTree.h?rev=314801&r1=314800&r2=314801&view=diff
>>>>> ============================================================
>>>>> ==================
>>>>> --- llvm/trunk/include/llvm/Support/GenericDomTree.h (original)
>>>>> +++ llvm/trunk/include/llvm/Support/GenericDomTree.h Tue Oct 3
>>>>> 07:33:41 2017
>>>>> @@ -702,28 +702,25 @@ public:
>>>>> return;
>>>>> }
>>>>>
>>>>> - unsigned DFSNum = 0;
>>>>> -
>>>>> SmallVector<std::pair<const DomTreeNodeBase<NodeT> *,
>>>>> typename DomTreeNodeBase<NodeT>::const_
>>>>> iterator>,
>>>>> 32> WorkStack;
>>>>>
>>>>> const DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
>>>>> -
>>>>> + assert((!Parent || ThisRoot) && "Empty constructed DomTree");
>>>>> if (!ThisRoot)
>>>>> return;
>>>>>
>>>>> - // Even in the case of multiple exits that form the post
>>>>> dominator root
>>>>> - // nodes, do not iterate over all exits, but start from the
>>>>> virtual root
>>>>> - // node. Otherwise bbs, that are not post dominated by any exit
>>>>> but by the
>>>>> - // virtual root node, will never be assigned a DFS number.
>>>>> - WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin()));
>>>>> + // Both dominators and postdominators have a single root node. In
>>>>> the case
>>>>> + // case of PostDominatorTree, this node is a virtual root.
>>>>> + WorkStack.push_back({ThisRoot, ThisRoot->begin()});
>>>>> +
>>>>> + unsigned DFSNum = 0;
>>>>> ThisRoot->DFSNumIn = DFSNum++;
>>>>>
>>>>> while (!WorkStack.empty()) {
>>>>> const DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
>>>>> - typename DomTreeNodeBase<NodeT>::const_iterator ChildIt =
>>>>> - WorkStack.back().second;
>>>>> + const auto ChildIt = WorkStack.back().second;
>>>>>
>>>>> // If we visited all of the children of this node, "recurse"
>>>>> back up the
>>>>> // stack setting the DFOutNum.
>>>>> @@ -735,7 +732,7 @@ public:
>>>>> const DomTreeNodeBase<NodeT> *Child = *ChildIt;
>>>>> ++WorkStack.back().second;
>>>>>
>>>>> - WorkStack.push_back(std::make_pair(Child, Child->begin()));
>>>>> + WorkStack.push_back({Child, Child->begin()});
>>>>> Child->DFSNumIn = DFSNum++;
>>>>> }
>>>>> }
>>>>>
>>>>> Modified: llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/
>>>>> Support/GenericDomTreeConstruction.h?rev=314801&r1=314800&r2
>>>>> =314801&view=diff
>>>>> ============================================================
>>>>> ==================
>>>>> --- llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h
>>>>> (original)
>>>>> +++ llvm/trunk/include/llvm/Support/GenericDomTreeConstruction.h Tue
>>>>> Oct 3 07:33:41 2017
>>>>> @@ -1349,6 +1349,102 @@ struct SemiNCAInfo {
>>>>> return true;
>>>>> }
>>>>>
>>>>> + // Check if the computed DFS numbers are correct. Note that DFS
>>>>> info may not
>>>>> + // be valid, and when that is the case, we don't verify the numbers.
>>>>> + static bool VerifyDFSNumbers(const DomTreeT &DT) {
>>>>> + if (!DT.DFSInfoValid || !DT.Parent)
>>>>> + return true;
>>>>> +
>>>>> + const NodePtr RootBB = IsPostDom ? nullptr : DT.getRoots()[0];
>>>>> + const TreeNodePtr Root = DT.getNode(RootBB);
>>>>> +
>>>>> + auto PrintNodeAndDFSNums = [](const TreeNodePtr TN) {
>>>>> + errs() << BlockNamePrinter(TN) << " {" << TN->getDFSNumIn() <<
>>>>> ", "
>>>>> + << TN->getDFSNumOut() << '}';
>>>>> + };
>>>>> +
>>>>> + // Verify the root's DFS In number. Although DFS numbering would
>>>>> also work
>>>>> + // if we started from some other value, we assume 0-based
>>>>> numbering.
>>>>> + if (Root->getDFSNumIn() != 0) {
>>>>> + errs() << "DFSIn number for the tree root is not:\n\t";
>>>>> + PrintNodeAndDFSNums(Root);
>>>>> + errs() << '\n';
>>>>> + errs().flush();
>>>>> + return false;
>>>>> + }
>>>>> +
>>>>> + // For each tree node verify if children's DFS numbers cover
>>>>> their parent's
>>>>> + // DFS numbers with no gaps.
>>>>> + for (const auto &NodeToTN : DT.DomTreeNodes) {
>>>>> + const TreeNodePtr Node = NodeToTN.second.get();
>>>>> +
>>>>> + // Handle tree leaves.
>>>>> + if (Node->getChildren().empty()) {
>>>>> + if (Node->getDFSNumIn() + 1 != Node->getDFSNumOut()) {
>>>>> + errs() << "Tree leaf should have DFSOut = DFSIn + 1:\n\t";
>>>>> + PrintNodeAndDFSNums(Node);
>>>>> + errs() << '\n';
>>>>> + errs().flush();
>>>>> + return false;
>>>>> + }
>>>>> +
>>>>> + continue;
>>>>> + }
>>>>> +
>>>>> + // Make a copy and sort it such that it is possible to check if
>>>>> there are
>>>>> + // no gaps between DFS numbers of adjacent children.
>>>>> + SmallVector<TreeNodePtr, 8> Children(Node->begin(),
>>>>> Node->end());
>>>>> + std::sort(Children.begin(), Children.end(),
>>>>> + [](const TreeNodePtr Ch1, const TreeNodePtr Ch2) {
>>>>> + return Ch1->getDFSNumIn() < Ch2->getDFSNumIn();
>>>>> + });
>>>>> +
>>>>> + auto PrintChildrenError = [Node, &Children,
>>>>> PrintNodeAndDFSNums](
>>>>> + const TreeNodePtr FirstCh, const TreeNodePtr SecondCh =
>>>>> nullptr) {
>>>>> + assert(FirstCh);
>>>>> +
>>>>> + errs() << "Incorrect DFS numbers for:\n\tParent ";
>>>>> + PrintNodeAndDFSNums(Node);
>>>>> +
>>>>> + errs() << "\n\tChild ";
>>>>> + PrintNodeAndDFSNums(FirstCh);
>>>>> +
>>>>> + if (SecondCh) {
>>>>> + errs() << "\n\tSecond child ";
>>>>> + PrintNodeAndDFSNums(SecondCh);
>>>>> + }
>>>>> +
>>>>> + errs() << "\nAll children: ";
>>>>> + for (const TreeNodePtr Ch : Children) {
>>>>> + PrintNodeAndDFSNums(Ch);
>>>>> + errs() << ", ";
>>>>> + }
>>>>> +
>>>>> + errs() << '\n';
>>>>> + errs().flush();
>>>>> + };
>>>>> +
>>>>> + if (Children.front()->getDFSNumIn() != Node->getDFSNumIn() +
>>>>> 1) {
>>>>> + PrintChildrenError(Children.front());
>>>>> + return false;
>>>>> + }
>>>>> +
>>>>> + if (Children.back()->getDFSNumOut() + 1 !=
>>>>> Node->getDFSNumOut()) {
>>>>> + PrintChildrenError(Children.back());
>>>>> + return false;
>>>>> + }
>>>>> +
>>>>> + for (size_t i = 0, e = Children.size() - 1; i != e; ++i) {
>>>>> + if (Children[i]->getDFSNumOut() + 1 != Children[i +
>>>>> 1]->getDFSNumIn()) {
>>>>> + PrintChildrenError(Children[i], Children[i + 1]);
>>>>> + return false;
>>>>> + }
>>>>> + }
>>>>> + }
>>>>> +
>>>>> + return true;
>>>>> + }
>>>>> +
>>>>> // Checks if for every edge From -> To in the graph
>>>>> // NCD(From, To) == IDom(To) or To.
>>>>> bool verifyNCD(const DomTreeT &DT) {
>>>>> @@ -1521,7 +1617,8 @@ bool Verify(const DomTreeT &DT) {
>>>>> SemiNCAInfo<DomTreeT> SNCA(nullptr);
>>>>> return SNCA.verifyRoots(DT) && SNCA.verifyReachability(DT) &&
>>>>> SNCA.VerifyLevels(DT) && SNCA.verifyNCD(DT) &&
>>>>> - SNCA.verifyParentProperty(DT) &&
>>>>> SNCA.verifySiblingProperty(DT);
>>>>> + SNCA.verifyParentProperty(DT) &&
>>>>> SNCA.verifySiblingProperty(DT) &&
>>>>> + SNCA.VerifyDFSNumbers(DT);
>>>>> }
>>>>>
>>>>> } // namespace DomTreeBuilder
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> llvm-commits mailing list
>>>>> llvm-commits at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Jakub Kuderski
>>>
>>
>>
>
>
> --
> Jakub Kuderski
>
--
Jakub Kuderski
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